Quantum-enhanced interferometry for new physics

现代物理学解释了从最小尺度到最大尺度的各种惊人现象，并已经彻底改变了世界！激光、半导体和晶体管是我们笔记本电脑、手机和医疗设备的核心。每年，英国和世界各地的国家量子技术计划都在开发新的量子技术，这些技术影响着我们的日常生活和基础物理学研究，并导致新的发现。光的量子态最近提高了引力波探测器的灵敏度，到目前为止，引力波探测器的探测已经吸引了公众，超导过渡边缘传感器现在用于天文学实验，以获得高分辨率的宇宙图像。尽管现代物理学取得了成功，但仍存在一些深刻而具有挑战性的问题。我们的联盟将利用量子技术的最新进展来解决两个最紧迫的问题：（i）暗物质的性质是什么？（ii）量子力学如何与爱因斯坦的相对论相结合？第一个研究方向的动机是大量的观察表明，星系中的物质的显着部分是没有直接观察到的光学望远镜。这种神秘的物质与引力相互作用，但似乎不发出任何光。了解暗物质的性质将有助于了解宇宙的历史和星系的形成，并将引发基础物理和可能的应用物理研究的新领域。尽管暗物质具有非凡的重要性，但它的本质仍然是一个谜。世界各地的许多最先进的实验正在寻找暗物质候选者，但迄今为止没有运气。我们建议搜索的候选者是轴子和类轴子粒子（ALP）。这些粒子是由粒子物理学中悬而未决的问题激发的，可能是暗物质的重要组成部分。首先，我们提出了一个实验，这将依赖于光的量子态，并将检测暗物质信号或改善现有的限制的轴子光子耦合的几个数量级的大范围的轴子质量。第二，我们将建立一个量子传感器，它将提高国际100米长的类轴子粒子ALPS探测器的灵敏度3 - 10倍。我们的第二条研究线致力于空间和时间的性质。谷歌最近宣布的西卡莫尔量子计算机和引力波的探测为量子力学和爱因斯坦相对论的成功实验测试提供了额外的证据。但是，引力如何与量子力学统一起来呢？为了寻找这个问题的答案，我们建议研究时空的两个量子方面。首先，我们将通过实验研究全息原理，该原理指出体积的信息内容可以在其边界上编码。我们将利用光的量子态，建造两台超灵敏的激光干涉仪，以前所未有的灵敏度研究空间不同区域之间可能的相关性。其次，我们将寻找近似解决量子引力问题的半经典引力模型的特征。我们将建造两台光学干涉仪，并首次在低温硅镜的运动中寻找半经典引力的特征。借助现代量子技术解决这些具有挑战性的基础物理问题，有可能为物理学研究开辟新的视野，并达到对我们生活的世界的新水平的理解。拟议的研究方向共享量子增强干涉测量的共同技术平台，并受益于参与该方案的研究人员的各种技能。

Modern physics explains a stunning variety of phenomena from the smallest of scales to the largest and has already revolutionized the world! Lasers, semi-conductors, and transistors are at the core of our laptops, cellphones, and medical equipment. And every year, new novel quantum technologies are being developed within the National Quantum Technology Programme in the UK and throughout the world that impact our everyday life and the fundamental physics research that leads to new discoveries. Quantum states of light have recently improved the sensitivity of gravitational-wave detectors, whose detections to date have enthralled the public, and superconducting transition-edge-sensors are now used in astronomy experiments that make high-resolution images of the universe. Despite the successes of modern physics, several profound and challenging problems remain. Our consortium will use recent advances in quantum technologies to address two of the most pressing questions: (i) what is the nature of dark matter and (ii) how can quantum mechanics be united with Einstein's theory of relativity?The first research direction is motivated by numerous observations which suggest that a significant fraction of the matter in galaxies is not directly observed by optical telescopes. This mysterious matter interacts gravitationally but does not seem to emit any light. Understanding the nature of dark matter will shed light on the history of the universe and the formation of galaxies and will trigger new areas of research in fundamental and possibly applied physics. Despite its remarkable importance, the nature of dark matter is still a mystery. A number of state-of-the-art experiments world-wide are looking for dark matter candidates with no luck to date. The candidate we propose to search for are axions and axion-like-particles (ALPs). These particles are motivated by outstanding questions in particle physics and may account for a significant part, if not all, of dark matter. First, we propose an experiment which will rely on quantum states of light and will detect a dark matter signal or improve the existing limits on the axion-photon coupling by a few orders of magnitude for a large range of axion masses. Second, we will build a quantum sensor which will improve the sensitivity of the international 100-m long ALPS detector of axion-like-particles by a factor of 3 - 10.Our second line of research is devoted to the nature of space and time. Recent announcements of Google's Sycamore quantum computer and the detection of gravitational waves have provided additional evidence to the long list of successful experimental tests of quantum mechanics and Einstein's theory of relativity. But how can gravity be united with quantum mechanics? To seek answers that inform this question, we propose to study two quantum aspects of space-time. First, we will experimentally investigate the holographic principle, which states that the information content of a volume can be encoded on its boundary. We will exploit quantum states of light and build two ultra-sensitive laser interferometers that will investigate possible correlations between different regions of space with unprecedented sensitivity. Second, we will search for signatures of semiclassical gravity models that approximately solve the quantum gravity problems. We will build two optical interferometers and search for the first time for signatures of semiclassical gravity in the motion of the cryogenic silicon mirrors.Answering these challenging questions of fundamental physics with the aid of modern quantum technologies has the potential to open new horizons for physics research and to reach a new level of understanding of the world we live in. The proposed research directions share the common technological platform of quantum-enhanced interferometry and benefit from the diverse skills of the researchers involved in the programme.